RT Journal Article
SR Electronic
T1 Characterization of Peripheral Nerve Sheath Tumors with 3T Proton MR Spectroscopy
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 1035
OP 1041
DO 10.3174/ajnr.A3778
VO 35
IS 5
A1 L.M. Fayad
A1 X. Wang
A1 J.O. Blakeley
A1 D.J. Durand
A1 M.A. Jacobs
A1 S. Demehri
A1 T.K. Subhawong
A1 T. Soldatos
A1 P.B. Barker
YR 2014
UL http://www.ajnr.org/content/35/5/1035.abstract
AB BACKGROUND AND PURPOSE: The characterization of peripheral nerve sheath tumors is challenging. The purpose here was to investigate the diagnostic value of quantitative proton MR spectroscopy at 3T for the characterization of peripheral nerve sheath tumors as benign or malignant, compared with PET. MATERIALS AND METHODS: Twenty participants with 24 peripheral nerve sheath tumors underwent MR spectroscopy by use of a point-resolved sequence (TE, 135 ms). Six voxels were placed in 4 histologically proven malignant peripheral nerve sheath tumors and 22 voxels in 20 benign peripheral nerve sheath tumors (9 histologically proven, 11 with documented stability). The presence or absence of a trimethylamine signal was evaluated, the trimethylamine concentration estimated by use of phantom replacement methodology, and the trimethylamine fraction relative to Cr measured. MR spectroscopy results for benign and malignant peripheral nerve sheath tumors were compared by use of a Mann-Whitney test, and concordance or discordance with PET findings was recorded. RESULTS: In all malignant tumors and in 9 of 18 benign peripheral nerve sheath tumors, a trimethylamine peak was detected, offering the presence of trimethylamine as a sensitive (100%), but not specific (50%), marker of malignant disease. Trimethylamine concentrations (2.2 ± 2.8 vs 6.6 ± 5.8 institutional units; P < .049) and the trimethylamine fraction (27 ± 42 vs 88 ± 22%; P < .012) were lower in benign than malignant peripheral nerve sheath tumors. A trimethylamine fraction threshold of 50% resulted in 100% sensitivity (95% CI, 58.0%–100%) and 72.2% (95% CI, 59.5%–75%) specificity for distinguishing benign from malignant disease. MR spectroscopy and PET results were concordant in 12 of 16 cases, (2 false-positive results for MR spectroscopy and PET each). CONCLUSIONS: Quantitative measurement of trimethylamine concentration by use of MR spectroscopy is feasible in peripheral nerve sheath tumors and shows promise as a method for the differentiation of benign and malignant lesions. Trimethylamine presence within a peripheral nerve sheath tumor is a sensitive marker of malignant disease, but quantitative measurement of trimethylamine content is required to improve specificity. MPNSTmalignant peripheral nerve sheath tumorNF-1neurofibromatosis type 1PNSTperipheral nerve sheath tumorSUVstandard uptake valuesTMAtrimethylamine